Light Infantry... what the ****

[Wendigo]

I use always a good amount of LI huskarls when playing Vanheim & Utgard Jotun.

With Vanheim I use them both for early expansion, and as a quick response force once the game advances thanks to their strategic move of 2: huskarls & mages can quickly be re-located, while the slower HI follow up at a slower pace.
Default Vanheim can also easily pull many trooper buffs that allow the humble huskarls to stand up on equal terms vs much heavier troops.

Same issue with Utgard-Jotun: the huskarls help compensate for the giant infantry troop density issues (one extra body+ one extra attack per square), and unlike HI they can keep up with the giant's movement rate.